Liquid crystal display devices can have a smaller thickness and lower power consumption. Therefore, the liquid crystal display devices are widely used as displays of television sets, OA equipment (e.g., personal computers), portable electronic devices (e.g., mobile phones and smart phones), and cockpits of vehicles, aircrafts, etc.
A liquid crystal display device includes a display panel and a backlight unit attached to a back surface of the display panel. The display panel includes an array substrate including switching elements (e.g., thin film transistors, etc.), a counter substrate facing the array substrate, and a sealing material bonding the array substrate and the counter substrate to each other. A liquid crystal material is enclosed in a space between the two substrates. The counter substrate is slightly smaller than the array substrate. Therefore, a terminal region of the array substrate is exposed. A drive circuit is mounted to the exposed terminal region.
The display panel includes a display region for displaying an image and a non-display region surrounding the display region.
An alignment film is provided on a surface of the array substrate contacting a liquid crystal layer to cover at least the display region. Similarly, an alignment film is provided on a surface of the counter substrate contacting the liquid crystal layer to cover at least at least the display region
The alignment film may be formed by performing rubbing treatment on a surface of a resin film of polyimide, etc. formed by flexographic printing, inkjet printing, etc. To form the resin film of polyimide, etc., inkjet printing is preferably employed for the following reasons: the resin film can be drawn directly on the substrate; contamination can be reduced due to the non-contact process; the amount of solution consumed can be reduced; the time required can be reduced; etc.
Incidentally, when inkjet printing is used to form the alignment film, a resin which is a material having a lower viscosity than when flexographic printing is used is used as a material of the alignment film. Therefore, the material of the alignment film tends to leak and spread out around a region (display region) in which the alignment film should be printed. Therefore, if the non-display region around the display region is so small that a large space cannot be ensured between the display region and a sealing member region, the alignment film may be formed to reach the sealing member region. In this case, the adherence between the sealing member and the alignment film is insufficient, and therefore, the gap between the two substrates cannot be completely sealed, so that the liquid crystal material of the liquid crystal layer may leak.
In order to solve the above problem, PATENT DOCUMENT 1 describes a liquid crystal display device including a groove portion, wherein the groove portion is provided in a generally annular region which is located outside the display region and inside the region to be provided with the sealing member, and the groove portion extends long along the periphery of the display region. With this configuration, even if the liquid resin material applied by inkjet printing spreads out of the display region, the groove portion can prevent the resin material from further spreading, whereby the spread outside the display region of the alignment film can be reduced or prevented. PATENT DOCUMENT 1 further describes a configuration in which a conductive film such as an ITO film is provided on a surface of the groove portion. The liquid resin material which is a material of the alignment film has a poor wetting property with respect to the ITO film. Therefore, with this configuration, the groove portion can reduce or prevent the spread outside the display region of the alignment film.